In my opinion using the wing/bcd for buoyancy with a drysuit increases the workload. In that the diver now has to manage two air spaces, not one. I've seen a number of uncontrolled ascents when divers (including instructors) forgot to dump gas from either the suit or wing/bcd.The dry suit is there to keep you dry and warm, not to control buoyancy with. That's what the bcd/wing is for. The dry suit should only hold enough air to avoid squeeze and give loft to your insulation. All you buoyancy needs should be covered by the bcd. This minimises workload and reduces the amount of air you need to juggle.
The only time I put gas in both is when diving below 35m, but when back above this depth I'm back to suit only.